9-160 based 13" sets started in L-line late 1979
its the 1980 model year. Used M & N line also. May have
spilt over to Y line but dont remember.
O-X are skipped over, any sets in that range are house
sets & not part of the regular line.
9-181 sets came in Y-line 1983 model year.
Again there may have been spill over.
If the AFC is in normal & the band switch is in air it should work.
You could also try it in special, that gives wider range
& longer search time for the AFC. Also try a VCR & see
if ch 3 is working.
If a 9-160 set on the 9-160 there is a little transistor called
32 V current source that will do this. Then look for PC cons
in the tuner area that is part of the 9-151 board.
On 9-181 sets tuner is separate. A little taping around may find
the problem.
73 Zeno